Internal-combustion engine



Dec. 16, 1924. l,519,8l4

I A. P. TRAsK INTERNAL coNBusTIoN ENGINE Filed May 24, 1922 3 Sheets-Sheet 2 Dec. 16,1924.

A. P. TRASK INTERNAL COMBUSTION ENGINE 3 Sheets-Sheet 3 f1 /X/ Filed May 24, 1922 /K/ Een., l5, i924.

" FFCE.

ALLAN :e TRASK, or BANGOR, MAINE.

NTERNAL-COMBUSTON ENGINE.

Application filed May 24,

To all iti/wm t may concern.'

Be it known that I, ALLAN F. TRAsii, a citizen of the United States, and resident of Bangor, county of Penobscot, State of Maine, have invented an Improvement in Internal-Combustion Engines, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts in each of the several views.

This invention relates to internal combustion engines more particularly of the fourcycle type, and has as its principal object the provision of an improved scavenging device supplemental to the usual or regular exhaust valve mechanism and adapted to take care of a major part of the products of combustion and a great part of the excessive heat, immediately at the end of the working stroke of the pistons thus relieving the regular exhaust valve, which is connected with the inner end of the cylinder, of the duty of discharging such heated products of combustion in large measure. lu accordance with my invention l provide means preferably associated with the piston, and also preferably borne by the piston for controlling an auxiliary exhaust port in proximity to the outer end of the cylinder in a manner so that such port is opened at the cud of the working stroke of the piston to permit the discharge of the products of combustion, but is not opened at the end of the suction stroke or at any other time except as required to permit the initial discharge of a major part of the products of combustion instantly as the working stroke is completed. The use of my invention by reason of the fact that it permits the immediate scavenging of the cylinder of the hot products of combustion to large extent instantly at the end of the working stroke; permits the use of a higher temperature at the beginning of the working stroke, i. e. with a substantially greater degree of compression of the charge, this being for the reason that the auxiliary exhaust device of my invention by permitting the quick and free discharge of the hot exhaust gases at each working stroke prevents the accumulation of heat within the cylinder. lhile the scavenging device of my invention is adapted for use with any known or suitable type of exhaust valve, such as the usual positively controlled poppet valves, or sliding sleeve valves, it is also well adapted and deT 1922. Serial No. 563,425.

signed for use with a rotary tubular exhaust valve which may be also employed in similar form for the inlet valve, for the particular reason that the regular exhaust valve being relieved of the duty of discharging a major portion of the most heated products of combustion, does not encounter such high temperatures as are involved in usual practice where the regular discharge valve has to take care of the entire exhaust. rIhe invention is herein illustratively shown as associated with a rotary tubular valve structure controlling both the exhaust and intake, and it is also shown as embodied in a water cooled engine, though by reason of the fact that the cylinder temperatures may be kept relatively much lower, the invention is well adapted for use in air cooled engines. The invention may be embodied in a great variety of dierent specitic forms in its broader aspects, a small number of such possible embodiments being shown herein for illustrative purposes and to typify the invention. The foregoing and other objects and advantages of the invention will more fully appear from the following detailed description taken in connection with the accompanying drawings, and the distinctive features of novelty will be pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a partial side elevation with portions broken away in vertical section of an engine embodying the invention;

Fig. 2 is a transverse section thereof on line 2-2 of Figure 1;

Fig. 3 is a partial sectional view corresponding to Figure 2, but with the valve head broken away, of a modified form;

Fig. l is a similar sectional View of a further moditied form; and

FiO'. 5 is a transverse section on line 5 5 of Figure t, and on a relatively reduced scale.

10 indicates an engine block, illustratively shown as having four cylinders 10a and with a valve head 11 secured to the top thereof. This valve head as shown is equipped with intake passages 12 and cxhaust passages 13 which are controlled by a rotary tubular inlet valve 14- and a rotary tubular exhaust valve 15, these valves being mounted to rotate in bearing saddles 16, 17 respectively which are fitted into gaps 18, 19 respectively, in the sides of the valve head, The exhaust valve has fitted thereiny a stationary exhaust manifold composed of inner and outer tubes 20, 2Gb, and suitable means indicated generally at 21 is provided for lubricating the exhaust valve. All these specific features of construction form no part of the present invention being set forth and claimed in other co-pending applications filed by me. Each cylinder 1()a is equipped with a usual spark plug 22 mounted in a firing chamber 23 and with suitable water jacketing 24, these also being conventional and illustrative for present purposes. In accordance with my invention the cylinder,-i. e. each of the cylinders 10, is equipped with an auxiliary exhaust port 25 in the locality of the outer extremity of piston movement. This port is preferably of relatively small dimension lengthwise of the cylinder, e. g. with a Width of about one quarter inch and with a length or angular extent circumferentially of the cylinder considerably greater, and suflicient to provide a port area to permit the free discharge of the products of combustion from the cylinder. These ports 25 may open into an exhaust manifold 26 secured to the engine block. 27 indicates the piston operative in the cylinder 10"L equipped with a usual wrist pin 28 for connection by means of a connecting rodv29 with a crank shaft of the engine (not shown). In accordance with my invention the piston is equipped with an extension or supplemental head or member borne thereby for limited movement with respect to the body of the piston and adapted to control the port 25, so that said port is opened at the end of each working stroke of the piston, but is not opened at the end of the suction stroke or at any other time. In the form of the invention shown in Figure 2 this is accomplished by means of a disc head 30 equipped with a short central stem 31 slidably fitted through a bore 32 in a central boss of the piston end with a head or nut 33 on the end of said stem limiting` lthe sliding movement thereof, and hence limiting the amount that the head 30 may be moved away from the end 27L of the piston.

A coil spring 34 may be interposed between the stem head 33 and the bearing boss of the piston. This head 30 preferably bears a packing ring 35 while the piston body 27 is equipped with other rings 36. The location of the port V25 is such that with the piston 27 at the outer end of its stroke, and with the head 30 lying flush with the piston end 27 a', the outer surface of the head 30 will just uncover said port, while with the piston in the same position, but with the head 30 drawn outward therefrom as far as permitted by its stem 31, the port 25 will be completely covered and closed from the interior' of the cylinder, the outer face of the head 30 then occupying the position indicated by the dotted line 30X. 'It may now be understood that in use, on the working stroke of the piston the pressure behind the same will hold the head 30 pressed against the piston end 27a, i. e. as shown in Figure 2, and thus at the end of the working stroke the port 25 will be opened to permit an instant and free discharge of the heated exhaust gases reducing both the pressure and the heat in the cylinder to a minimum. Thereupon the inward scavenging stroke clears the cylinder as usual, with the condition however that the exhaust valve 15 inthe valve head is only required to takecare of the residue of the products of combustion which has already been relieved of the greater part of its heat and of substantially all of its pressure. Then on the next outward stroke which draws in the fresh charge, the'head 30 will lag behind the piston body 27, being retarded both by the suction thereon and by the drag of the packing ring. Thus at the end of the suction st-roke the outer face of the head 30 will occupy the position in 7 dicatcd at 30X keeping the port 25 covered, it being here noted that the movement thus permitted of the head 30 with respect to the piston body is slightly greater than the width of the port 25, e. g. with a port width of one-quarter inch, this relative movement of thc head 30 should be about five-sixteenth inch. Then on the next inward movement of the piston to compress the charge, the head 30 is pressed against the end of the piston by the compression and also by the drag of the packing ring. Means is preferably provided to cushion the movement of the head 30 in each direction, so that it Y will be substantially noiseles's. For this purpose I preferably employ a fluid cushion, which may be conveniently provided in a manner so as to permit the movement of the head 30 in each direction as quickly as necessary, and still without impact or hammering, by providing a vent 37 ofV suitable dimension to the space between the outer face of the piston body and the inner face of the head 30. Thus the head 30 is permitted to move outward or inward with respect to the piston body only so fast as the air trapped therebetween can nd vent through the port 37, and by gauging the dimension of this port the requisite cushion effect may be obtained to a nicety, while still permitting the movement of the head 30 with respect to the pistonbody to be as rapid as necessary for its designed purpose. In Figure 3, I show a form of the invention wherein the `auxiliary exhaust port 25 is controlled by a inovably mounted extension or fitting on the piston' body 277 operative in the same way but structurally somewhat different from that already described. In this case the outer end portion of the piston body is rebated circumferentially to provide a reduced end boss or projection 38, and upon this boss 38 a. cap head 39 is fitted for limiting sliding movement. The boss 3S is equipped near its outer extremity with a peripheral groove in which is fitted an expanding ring 40 which may be similar to a` usual packing ring and this ring engages an internal bearing surface 4l of the cap 89, which is provided at its inner extremity with a ledge 42 adapted to engage the ring 40 to limit the outward movement of the cap 39 with respect to the piston body, the movement of the cap with respect to the piston body thus permitted being preferably about live-sixteenth inch as already described. The sides of the cap 39 may be provided with holes 40, permitting a tool to be passed therethrough for compressing the ring 40 so as to permit the cap to be removed when required. In this case the cap 39 presents a relatively extended bearing surface to the cylinder and it is shown as equipped with two packing rings 42, 43. 'l'he ring 42 may be of usual dimension, but the outer ring 43 is preferably wide, the reason for this being that as the piston nears the inner end of its travel, it is desirable that this ring should not pass wholly beyond the point indicated at 44 between the end of the cylinder block and the valve head which might result in a catching of the ring upon the minute ledge of the cylinder at this point with possibilities of great damage to the parts. In this case also a fluid cushion is provided in the space 45 between the cap and the outer surface of the piston boss 3S, the effect of which may be modified by a port 46 of proper dimension as already explained. ln this case the cap 39 is pressed down upon lthe piston end on the working stroke so as to open the port at the end of such stroke, and lags be-I hind the piston body on the suction stroke, so that it covers the port 25 at the end of such stroke as shown, and as already explained in the first described form of the invention. In Figures 4 and 5 I show a form of the invention where the piston body 27 as a whole has a limited movement with respect to the wrist pin 28 and connecting rod 29 which are engaged therewith. ln this case the wrist pin 28 is fitted to a cross head 47 which is fitted for limited sliding` movement in bearings 4S provided within the shell or skirt portion of the piston. The extent of such relative sliding movement is limited by a ring 49 threaded into the outer portion of the piston shell and having cooperative therewith a locking ring 50. Thus by the adjustment of this ring 49, the extent to which the piston body 27 is permitted to lag behind the cross head 47 on the suction stroke may be regulated and determined so that the port 25 will not be uncovered on the suction stroke as already explained. In this case the cross head 47 may be equipped with an outwardly extending plunger member 5l fitting within a socket 52 provided by a shroud or sleeve 53 formed interiorly of the piston body, this providing a fluid cushion, which may be relieved in predetermined degree by a port 54 shown as formed in one side of the plunger' 51. lt will be understood that the operation of this form of the invention is precisely similar to that already explained. with the port 25 un` covered at the end of each working stroke only to take off the pressure and heat within the cylinder before the scavenging stroke begins. l am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. and l therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having described my invention, what l claim as new and desire to secure by Letters Patent is:

l. A four-cycle internal combustion engine comprising a cylinder, valve mechanism for controlling the intake and exhaust to the inner end thereof, an auxiliary exhaust port adjacent the outer en'd of the cylinder, a piston operative in the cylinder, and means associated withand borne by the piston for controlling said auxiliary exhaust port whereby it is opened at the end of each working stroke to the cylinder and closed at all other times.

2. A four-cycle internal combustion engine comprising a cylinder, a piston operative therein, valve mechanism controlling the intake and exhaust to the inner end of the cylinder, an auxiliary exhaust port adjacent the outer end of the cylinder, and means borne by the piston Controlling said port whereby it is opened at the end of each working stroke to the interior of the cylinder and closed at all other times.

3. A four-cycle internal combustion engine comprising a cylinder, valve mechanism controlling the intake and exhaust to the inner end thereof, a piston operative in the cylinder, an auxiliary exhaust port in the cylinder adjacent the outer limit of travel of the piston, and means assocoated with the piston and having a limited movement with respect to the body of the piston, adapted and arranged to control said port to open the same at the end of each working stroke, and to keep the same closed at the end of each suction stroke thereof.

A four-cycle internal combustion engine comprising a cylinder, positively operated valve mechanism controlling the intake and exhaust to the inner end thereof, a piston operative in the cylinder with connections to a crank shaft, a port in the cyllll.)

inder adjacent the outer` extremity of piston movement therein, and means embodying a lost motion of the Outer face of the piston with respect to said connections to the crank Y shaft, constructed and arranged to open said port at the end of each Working stroke of the piston and to keep said port closed at the end of each suction stroke and at all other times.

A four-cycle internal combustion engine comprising a cylinder, a piston operative therein, valve mechanism controlling the intake and exhaust to the inner end of the cylinder, an auxiliary exhaust port adjacent the outer limit of travel of the piston, said port being of relatively small dimension lengthwise of the cylinder and relatively extended circun'iferentially thereof, a connection from the piston to a crank shaft, and means embodying a lost motion i of the outer face of the piston With respect to said crank shaft connection for controlling said port toy open the same at the end of each Working stroke and permit clearing of the cylinder of Working pressure and heat, While keeping said port closed at the end of each suction stroke and at all other times.

6. A four-cycle internal combustion engine comprising a cylinder, a piston operative therein, valve mechanism controlling the intake and exhaust tothe inner end of the cylinder, an auxiliary exhaust port adjacent the outer end of the cylinder, and means borne by the piston controlling said port whereby it is opened at the end of each Working stroke to the interior of the cylinder and closed at all other times, said means equipped With a cushioning device to regulate the functioning thereof.

7. A four-cycle internal combustion engine comprising a cylinder, a piston operative therein, valve mechanism for controlling the intake and exhaust to the inner end thereof, an auxiliary exhaust port a'djacent the outer end of the cylinder, apiston operative in the cylinder, and means associated with the p-iston for controlling said auxiliary exhaust port whereby it is opened at the end of each Working stroke to the cylinder and closed at all other times, said mea-ns equipped with provision for fluid cushioning to regulate the functioning thereof.

8. A four-cycle internal combustion engine comprising a cylinder, valve mechanism for controlling the intake and exhaust thereto, a piston operative in the cylinder with connections to a crank shaft, a port in the cylinder adjacent the outer extremity of piston movement therein, and means embodying a lost motion of the face o-f the piston with respect to said connections constructed and arranged to open said port at the end of each Working stroke of the piston and to keep said port closed at all other times, said means equipped with provision for iiuid cushioning to regulate the functioning of such lost motion.

9. In a four-cycle internal combustion engine, a cylinder having an auxiliary exhaust port adjacent the outer end thereof,

and a piston operative therein With connections to a crank shaft, said connections embodying a lost motion between the operative Iface of the piston and the crank shaft and equipped with a iiuid cushion device arranged and disposed to regulate the functioning of such lost motion.

10. A four-cycle internal combustion engine comprising a cylinder, a piston operative therein, a rotary tubular valve controlling the exhaust to the inner end of the cylinder, an auxiliary exhaust port adjacent the outer end of the cylinder, and means associated With and borne by the piston for controlling said auxiliary exhaust port whereby it is opened at the end of each Working stroke to the cylinder and closed at all other times.

In testimony whereof, I have signed my name to this specification.

ALLAN P. TRASK. 

